Field of the Invention
The present invention relates to a damper structure of clutches for use in internal combustion engines for vehicles, mainly for saddle-riding type vehicles such as motorcycles, three-wheeled vehicles, and four-wheeled buggies.
Description of Related Art
As clutches for use in internal combustion engines of vehicles, it has been known that a clutch that has a damper, for damping torque, is interposed between a driving-side rotary member and a driven-side rotary member, and absorbs variation in torque that is generated in a power transmission system for an internal combustion engine (for example, JP Examined Utility Model Publication No. 03-002031).
In a structure having such a damper, a deformation margin for the damper needs to be assuredly provided in order to reduce shock. However, in a case where an axial clearance between the damper and the driven-side rotary member is increased so as to assuredly obtain such a deformation margin, an axial position of the damper is rendered to be unstable. Further, in a case where the axial clearance is increased, the outer circumferential surface of the damper to be pressed by a clutch gear of the driving-side rotary member is offset in the axial direction, and a portion of the outer circumferential surface of the damper may not be pressed, which may increase a load per unit area of the outer circumferential surface of the damper accordingly. Therefore, a width (dimension in the axial direction) of the clutch gear needs to be increased, which leads to increase in weight.